2006-12-16 14:04:38 · 3 answers · asked by faye 1 in Science & Mathematics ➔ Astronomy & Space
The shadow-casting edge, called the gnomon, must not only point north, for best usage it must also be pointing to the North Celestial Pole at your location. That means you need to know your latitude.
Example: suppose that you measure the angle of the gnomon and find that it's 40°. If your latitude is 40°, that's great: just position the sundial level and point the gnomon directly north. But suppose your latitude is 37°. In that case, leaving the gnomon level would mean that it's pointing too high in the sky; you would need to shim up the south side of the sundial by three degrees to make it give the time correctly.
On the other hand, if your latitude were 45°, the gnomon would be pointing too low if the dial were level, so you would need to shim up the north side by five degrees.
But if all you want is something decorative, you can mount it level and pointing north, and you'll get a very nice artifact that gives a very approximate time.
2006-12-16 14:37:47 · answer #1 · answered by Keith P 7 · 1⤊ 0⤋
Set it level with the gnomon (pointy shadow making thing) pointing due north. Not magnetic north, true north.
2006-12-16 22:11:41 · answer #2 · answered by campbelp2002 7 · 0⤊ 0⤋
the sun rises in the east and sets in the west
and set it toward true noth. check your setting at high noon and see where you are off
2006-12-16 22:07:59 · answer #3 · answered by Donald D 2 · 0⤊ 0⤋